Condition responsive high-voltage gate

ABSTRACT

Gating circuitry for ultraminiature light sources. Each gate comprises a plurality of input means which are connected to a different high-voltage pulse source and an output means connected to the electrode of an ultraminiature light source. One of the plurality of input means includes a resistor and the remainder of the inputs each includes a diode. The plurality of input means are connected to output means so that the gate energizes the light source upon coincidence of a pulse generated at each of the voltage sources.

nited tntes tent [72] Inventors Andrew E. Trollio 210 Carlton Ave,lBroornall, Pa. 19008; Edward G. Busch, 454 Marlin Road, Newton Square,lPa. 119073 [21] Appl. No. 863,026 [22] Filed Sept. 29, 1969 [45]Patented Nov. 2, 1971 Continuation of application Ser. No. 507,145, Nov.110, 1965, now abandoned,

[54] CONlDlITlON RESPONSTVE HIGH-VOLTAGE GATE 3 Claims, 8 Drawing Tigs.

[52] ILLS. C1. 328/94, 315/269, 178/15, 307/218 [51] lint. Cl ll-ll03lr117/74 [50] Field of Search 328/94 {56] References Cited UNITED STATESPATENTS 2,580,771 1/1952 Harper 328/94 2,797,318 6/1957 Oliwa 328/943,196,445 7/1965 Trolio.... 346/1 2,970,303 1/1961 Williams 328/94Primary Examiner- Donald D. Forrer Assistant Examiner-Harold A. DixonAttorney-Caesar, Rivise, Bernstein & Cohen ABSTRACT: Gating circuitryfor ultraminiature light sources. Each gate comprises a plurality ofinput means which are connected to a different high-voltage pulse sourceand an output means connected to the electrode of an ultraminiaturelight source. One of the plurality of input means includes a resistorand the remainder of the inputs each includes a diode. The pluralityofinput means are connected to output means so that the gate energizesthe light source upon coincidence ofa pulse generated at each of thevoltage sources.

CGNIDTTIIGN MESIPONSWE ll-llliGliil-VGLTAGE GATE This application is acontinuation of application Ser. No. 507,145 filed Nov. 10, 1965, nowabandoned.

This invention relates generally to high-voltage-driving techniques andmore particularly to a gate responsive to a plurality of conditions fordriving a high-voltage circuit.

There are many instances where high voltage is necessary to drive orenergize an output circuit. One example of a device requiring highvoltage is the ultraminiature light source which uses high voltage tobreak down the gap between a pin electrode and bar electrode in order toproduce an are which provides an ultraminiature source of light. Anexample of such an ultraminiature light source is shown in US. Pat. No.3,196,445 which issued July 20, 1965 to Andrew E. Trolio. In such anultraminiature light source, a plurality of pin electrodes are arrangedin a rectangular pattern in order to produce by combinatorialenergization of selected ones of said electrodes, a numerical oralphanumerical character which can be recorded by light sensitive paper.

Typically, a number of ultraminiature light sources are used together inorder to produce a word or large number. That is, since eachultraminiature light source can produce an alphabetical or numericalcharacter, a plurality of these characters are used together to puttogether a word or long number. In a typical example, 20 pin electrodesin rows of four and columns of five are used in a numeric light source.Thus, if a numerical representation in the millions is desired, it isnecessary to use seven of these light sources together. In the past, ithas been necessary to use one power amplifier to fire each pinelectrode.

Thus, in the example given, it would have been necessary to use oneamplifier for each pin electrode in each of the light sources or a totalnumber of 140 (20x7) power amplifiers. Further, the number of amplifiersneeded presents a packaging problem due to the size of the amplifierseven with solidstate circuitry. It has been recognized that due to theextremely high speed at which the ultraminiature light source isenergized, and the short duration of the energization it would not benecessary to use all of the amplifiers if the light sources wereenergized sequentially. Thus, instead of 140 amplifiers, the 20amplifiers used for a first of these light sources could also be usedfor the six additional light sources as they are sequentially arced.However, in addition to the 20 amplifiers, it is also necessary toprovide a gating system which selects only one of the light sources forenergization at a time by the amplifiers. In such a sequential system,it is therefore desirable to have coincidence gates which are capable ofsteering the necessary high voltage to the individual pin electrodes tofire them.

Existing gates, however, have not been able to handle this problembecause they are so inefficient or because the gages have not beenreliable.

One coincidence gating method that has been used to fire a pin electrodea light source comprises application of half the breakdown voltage tothe pin electrode and a similar inverted voltage to the bar electrode.Thus, upon coincidental application of the aforesaid voltages thevoltage differential between the bar and pin electrodes is equivalent tothe breakdown potential of the ambient air that forms the gap betweenthe electrode and bar. This system, however, is highly erratic and oftenresults in firing of pin electrodes within a light source when notintended. That is, on a moist day, the breakdown potential of the gap isless than on a dry day. Therefore, since half of the breakdown voltageis applied to either the pin or bar electrodes whenever an input ispresent, the one input alone can overcome the breakdown potential anddrive an arc across the gap if the conditions are right. Further, withnormal variations in arc-gap dimensions, wear and tear in use, andvarious other factors, voltage ranges over which the pin may or may notfire, or ionize, overlap. There is also the probability that the gap maybe enlarged and the application simultaneously ofa pulse to both the pinand the bar will not fire the pin. This probability is enhanced becausethe possibility of only one pulse causing an arc prevents using a largervoltage to overcompensate for wear. Another problem with theaforementioned method is that the gap between the electrode and bar is"floating electronically (that is, neither the electrode nor bar isgrounded) and, therefore, spurious pickup and radio interferenceproblems are aggravated.

It is, therefore, an object of this invention to provide a new andimproved gate which overcomes the aforementioned disadvantages.

It is another object of the invention to provide a new and improved gatefor driving a highvoltage circuit in accordance with the simultaneousoccurrence of a plurality of conditions.

It is another object of the invention to provide a high voltage gatewhich is adapted to drive a plurality of high voltage circuits.

Another object of the invention is to provide a new and improved systemfor sequentially energizing a plurality of high voltage circuits.

Yet another object of the invention is to provide a new and improvedhigh-voltage gate which is inexpensive to manufacture and which isextremely reliable.

The aforementioned as well as other objects are achieved by providing agate for energizing a circuit requiring high input voltage for operationthereof, said gate comprising a plurality of input means each connectedto a different high voltage pulse source and an output means connectedto said circuit, one of said plurality of input means including aresistor. the remainder of said plurality including a diode, saidplurality of input means each connected to said output means so thatsaid gate energizes said circuit upon coincidence of a pulse generatedat each of said voltage sources.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

FIG. l is a schematic diagram of a high-voltage gate embodying theinvention;

FIG. 2 is a diagrammatic schematic block diagram of aphotographic-recording system embodying the invention;

FIG. 3 is a diagrammatic schematic block diagram of anotherphotographic-recording system embodying the invention;

FIG. 4 is a schematic diagram of a two input gate embodying theinvention and the logic block diagram representation thereof;

FIG. 5 is a schematic diagram of a three-input gate embodying theinvention and the logic block diagram representation thereof;

FIG. 6 is a diagrammatic elevational view of a face of an ultraminiaturelight source;

FIG. 7 is a schematic block diagram of a photographic printer embodyingthe invention;

FIG. 8 is a schematic diagram of a four-input gate having pluralparallel outputs and the logic block diagram representation thereof.

Referring now in greater detail to the various figures of the drawingswherein similar reference characters refer to similar parts, ahigh-voltage gate embodying the present invention is generally shown at20 in FIG. 1. Gate 20 is generally comprised of a resistor 22, a diode Mand associated circuitry. Resistor 22 and diode 2d are connected to eachother via junction 26. Additional diodes 2d are also connected tojunction 26 where more than two inputs are used. Thus, for N inputs, N-ldiodes are used.

The input including resistor 22 of the gate 20 is connected via inputlead 30 to the secondary winding 32 of transformer 34 The primarywinding 36 of the transformer 34 is connected to the output of a poweramplifier (not shown). The input including diode 24 is connected tosecondary winding 3% of transformer 40. The primary winding 42 oftransformer 40 is connected to the output of a second power amplifier(also not shown.) Transformers 3d and it) are both step-up voltagetransformer. Capacitor M which is connected across secondary winding 32of transformer 34 may be a physical capacitor but is preferably thedistributed capacitance across the transformer. Similarly, capacitor 46which is connected across the secondary winding 38 of transformer 40 mayalso be a physical capacitor but is preferably the distributedcapacitance across the transformer.

The secondary winding 32 and the capacitance 44 are connected to groundas are secondary winding 38 and capacitance 46. Each additional diode 28that is connected to the basic gate 20 has a similar input circuit (notshown) to that of diode 24.

Connected to the output junction 26 of the gate 20 is a pin electrode 48of an ultraminiature light source. lt is separated by a gap 50 from abar electrode-52 which is connected to ground.

in operation, if a voltage pulse is simultaneously applied by poweramplifiers to primary winding 36 and 42, the transformers 34 and 40,respectively, step up the voltage pulse and a high-voltage pulse outputis produced at junction 26 of the gate which is transmitted to the pinelectrode 48. The output voltage produced at both of the secondarywindings 32 and 38 is individually large enough to break down the gap 50and cause arcing between electrodes 48 and 52.

Only when a positive pulse is applied to both transformers 34 and 40 issuch arcing produced. That is, the arcing does not occur under any otherconditions. If no pulse is provided to transformers 34 or 40, there isno change of voltage at junction 26 and thus no voltage differentialacross the gap 50. If a pulse is applied only to transformer 34, thevoltage rises across resistor 22 and forward biases diode 24 therebyconverting diode 24 into a conductor. The voltage at junction 26 is thusattenuated by virtue of the fact that capacitance 46 and the inductanceof the transformer 40 in parallel form a low-impedence path to groundpotential. Thus, the voltage at junction 26 rises only slightly incomparison to the voltage from transformer 34. Thus, very little voltageis applied to pin electrode 48 and the pin is not fired.

If a pulse is applied to transformer 40 alone, the voltage at the outputof secondary winding 38 back biases diode 24 thereby causing isolationor an effectively open circuit between the input to the diode 24 and thejunction 26 which thereby prevents a rise of voltage across the gap 50of the light source. Thus, it can be seen that a single pulse alongcannot inadvertently fire pin electrode 48.

' However, when voltage pulses are applied to primary windings 36 and 42of transformers 34 and 40 respectively,

diode 24 remains nonconductive because the voltage provided at thesecondary winding 38 is enough to hold off the pulse at the output ofsecondary winding 32. Thus, since diode 24 does not conduct, the winding38 and capacitance 42 do not provide a. low-impedence path to ground forthe pulse from secondary winding 32. Thus, the voltage at junction 26reaches the breakdown potential of gap and an arc is produced betweenelectrodes 48 and 52. Thus, it can be seen from the above descriptionthat the voltage at the output of transformer 34 actually drives theelectrode to are the gap. This means that the input to the input of thegate including resistor 22 is the only input which need be connected toa highpower driver. This factor can effect substantial economies where alarge number of gates are required.

As previously mentioned, the capacitances 44 and 46 of transformers 34and 40 are not necessarily capacitors which are placed across thesecondary windings of the transformer. It is preferable that thetransformer design of transformer 40 be such that the capacitancethereof permits conduction of the pulse from the transformer 34 toground to prevent output voltage at junction 26 to cause firing of thepin electrodes. It should also be noted that the transformers used ateach of the inputs of the gate 20 are not just an added component to addcapacitance. The transformers are necessary between the power amplifiersource and the input to the gate to couple as well as to step up thevoltage from the power amplifier to the breakdown potential. Thecapacitance across transformer 40 does not in any way affect the pulsethat fires the pin electrode 28 because diode 24 is back-biased therebyisolating the capacitance when the electrode is fired. As the gap isarced, the voltage at junction 26 drops very quickly to ground. Thepower amplifiers, however, are not afi'ected because the transformer 40is isolated by the diode 24 and transformer 32 is bypassed by thecapacitance 24 to ground.

Where additional inputs including diodes 28 to gate 20 are used, the pinelectrode cannot be fired unless each input is coincidentally pulsed.Any combination of input pulses less than the number of inputs to thegate 20 fail to produce an output voltage adequate to fire the pinelectrode 48. When a single voltage pulse is applied to resistor 22, thediodes 24 and 28 are forward biased and provide a parallel low-impedencepath to ground through the secondary windings and capacitances of thetransformers associated therewith. lf voltage pulses are applied to oneor each of diodes 24 and 28, the back-biased diodes isolate the outputjunction 26 from the input pulses thereby preventing the pin 48 fromfiring. Finally if an input pulse is applied to resistor 22 and to atleast one of diodes 24 and 28 but not to each of them, the diode whichhas not been pulsed is forward biased and provides a low-impedence pathto ground thereby attenuating the voltage at junction 26. Thus, unlessinput pulses are applied simultaneously to all the inputs of the gate20, the output voltage at junction 26 is not sufficient to cause arcingbetween electrodes 48 and 52.

The breakdown voltage of gap 50 is typically in the area of 1,200 volts.Thus, it can be seen that very high voltages can be handled by gate 20especially when compared to the normal low-voltage ranges that aretypically handled by solid-stategating circuitry. in addition, thereliability of the gate is extremely good. The probability of a pinelectrode firing as a result of only one input pulse is extremely lowbecause only a very small voltage is applied to output junction 26unless all of the inputs are pulsed. The grounding of the bar electrode58, also prevents inadvertent firing or prevention of firing due tospurious pulses being picked up. Since only a very small voltage isapplied to junction 26 when less than all of the inputs are pulsed, thevoltage applied to junction 26 when all of the inputs are pulsed may besubstantially larger than the normal breakdown voltage of the gap. Inthis manner, the danger of not firing as a result of normal wearing orgap and pulse variations is substantially reduced without substantiallyincreasing the probability of inadvertent arcing.

The design of the gate is such that even though high voltages are usedto fire the pin electrode 48, low power solid-state devices may be usedthroughout. The reason is that high voltage is applied to resistor 24 inshort duration pulses only. Pulses of microseconds duration are used.Thus, resistor 22 need have only a very low power rating. Further, thevoltage pulses applied to the diode inputs of the circuit merely inhibitthe forward biasing of the diodes, thus, high-power amplifiers are notnecessary to drive the transformers associated with the diode inputs ofthe circuit.

A system of firing light sources for a recorder embodying the inventionis shown diagrammatically in FIG. 2. The gating system shown in FIG. 2is used to sequentially fire a plurality of ultraminiature light sources54, 56, 58...60. Each light source has twenty pin electrodes 48 as showndiagrammatically in FIG. 6. The mounting 62 for the ultraminiature lightsource is composed primarily of an insulating material and includes adielectric material which is placed between the pin electrodes 48 andbars 52. When a pulse is applied to a pin electrode 48 the voltage levelof which is in excess of the critical potential necessary to cause abreakdown in the air at the area of the exposed tips of the electrodes,an electrical arc is created between the pin electrode 48 and theelectrode bar 52 which, as previously seen, is maintained atsubstantially ground potential. The are occurs only at the exposed tipof the electrode because the dielectric layers of insulator mounting 62have a dielectric strength in excess of the ambient air which does notpermit an electric breakdown therethrough at the potential which is usedto breakdown the air. The electrical discharge between the electrodes 66and 62 is therefor substantially parallel to the front edge 66 of theultraminiature light source.

The ultraminiature light source shown in H6. 6 is adapted to displaynumerical figures only. That is, only 20-pin electrodes are used in thelight source shown in MG. 6. Where alphabetic characters are alsorequired, 25-pin electrodes are used. Thus, if the numeral 2 is producedby the light source oflFlG. 6, pins numbered ll, 2, 6, l, 6,112, ll, i6,6, l3, l7, l6, l6 and 26 are fired simultaneously thereby producing theform of the numeral 2.

in the system of lFlG. 2, seven light sources 66, 56, 56.66 are used.The forth through sixth of these light sources are not illustrated inorder to clarify the figure. Also not illustrated for the purpose ofclarity, is the photosensitive paper of film which passes closelyadjacent the front edges of the light sources 66 through 66 and whichrecords the numbers produced by the light sources.

A plurality of gates are connected to the input of the pin electrodes 66of the light sources 66, 56, 66.66. 20 gates 66 are connected to the pinelectrodes 66 of light source 56. The gates used throughout MG. 2 areillustrated as semicircles with dots therein. As shown in lFlG. 66, eachgate having two inputs and an output is equivalent to the gate shown inH6. 66. which has a first input including resistor 22 and a diode 26included in the second input which are secured together at outputjunction 26.

The 20 gates 66-ll through 66-26 are each connected to the correspondingpin electrode of the light source 6'6, however, in order to clarify thediagram of lFlG. 2, only two gates 66-1 and 66-26 which are connected topin electrodes 66 in positions l and 26 respectively of the light sourceare shown. Similarly, there are 20 gates 66-l through 66-26 which areconnected to the corresponding pin electrodes of light source 56, butonly gates 66-1. and 66-26 are shown which are connected to the pinelectrodes 66 in positions l and 26 respectively of light source 56. 20gates 76 are connected to the corresponding pin electrodes of lightsource 56, however, only gates 76-6 and 76-26 which are connected to pinelectrodes 66 in positions )1 and 26 respectively of the light source 56are shown. Finally, 20 gates 72 are connected to the corresponding pinelectrodes of light source 66, however, only the gates 72-l and 72-26which are connected to pin electrodes 66 in locations l and 26 thereofare shown. There are also twenty gates provided for each of the fourththrough sixth light source which are also not shown for the purpose ofclarity.

A stream of characters are supplied by a character source 76 to thevarious light sources. Source 76 provides a parallel J output on outputlines 76-ll through 76-26 of 20 pulses in a combinatorial binary oron-off code in order to produce the form of the character in a selectedlight source.

Thus, the twenty output leads 76 are fed the combinatorial signals inparallel. if a numeral 2 is desired on one of the light sources, thefollowing lines 76 of the source would be energized: 76-l, 76-2, 76-3,76-6, 76-6, 76-312, 76-111, 76-16, 76-6, 76-l2l, 76-27, 76-163, 76-6 and76-26. The remaining lines, of course, would not be energized.

Character source 76 includes an oscillator and 20 gates which areenabled at predetermined intervals by the oscillator. The characterinformation inputs are applied to the gates which transmit theinformation to output lines 76-11 through 76-26 output pulses.

Each of the lines 76 from the character source 76 is connected to apower amplifier 76. Twenty power amplifiers 76-11 through 76-26 areprovided and they are each connected in turn to transformer 66-l through66-26, respectively. There are also 20 transformers 66-1 through 66-26.Only two of the output lines 76-ll and 76-26, two of the amplifiers 76-land 76-26, and two of the transformers 66-i and 66-26 have been shown inorder to clarify the diagram.

Transformers 66-l through 66-26 are each connected to the correspondinggates of each of the light sources 56, 56,

66.66. That is, transformer 66-6 is connected to gates 66-ll, 66-11,76-ll...72-l. Similarly, transformer 66-26 is connected to the inputs ofgates 66-26, 66-26, 76-26...72-26. A column selector 62 is providedhaving seven output lines 66-11 through 66-7. The column selector isadapted to sequentially energize the output lines and is comprised of aseven-stage ring counter having an output line talten from each stage.interposed between the output lines of the counter and the output lineslid-ll through 66-7 are seven gates. An oscillator is connected to eachof the gates to provide pulse outputs sequentially on lines 66-7.through 66-7. One stage of the counter is energized at a time. The stagewhich is energized enables the associated one of the gates of the columnselector to pass a pulse from the oscillator. After a pulse is generatedby one of the gates, timing pulses applied via line 66 from thecharacter source to the column selector shift the counter so that thenext stage of the counter is energized. After each stage has beenenergized in sequence, the first stage is again energ zed and theprocess is repeated. The output lines 66-2 through. 66-7 are connectedto seven amplifiers 66-ll through 66-7. Amplifiers 661i through 66-7 areenergized by the pulse on the associated output line 66 from the columnselector 62. The amplifiers 66 are connected to the seven transformers66 which are numbered 661i through 66-7.

Transformer 66-2 is connected to each of the gates 66-11 through 66-26.Transformer 66-2 is connected to each of gates 66-ll through 66-26. andsimilarly transformers 66-3 through 66-7 are connected to the gatesassociated with light sources 66 though 66 respectively.

Transformers 66-l through 66-26 are each analogous to transformer 66 inH6. l in that they are connected to the input including diode 26 of thegate. Transformers 66-l through 66-7 are analogous to transformer 36 inthat they are connected to the input including resistor 22 of the gate.The reason for connecting the transformers in this manner is that thepower used to fire the pin electrodes is derived from the poweramplifier connected to transformer Thus, since only seven transformersare used, it is more economical to provide only seven high-poweramplifiers to drive the transformers 661i through 66-7 than to provide20 high-power amplifiers to drive transformers 66-1 through 66-26.

In operation, character source 76 supplies via amplifiers '76- 11through 76-26 a combinatorial parallel signal to the various groups ofgates 66, 66, 76 and 72. The column selector simultaneously selects oneof the groups of gates 66, 66, 76 or 72 in accordance with the state ofthe counter within column selector 62. Thus, if output line 66-11 isenergized, the amplifier 66 provides a pulse to transformer 66-li whichprovides an input pulse to gates 66-ll through 66-26. Thus, if thecombinatorial code for the number 2 is supplied via lines 76 of thecharacter source 76, gates 66-i 66-2, 66-3, 66-6, 66-6, 66-l2, 66-i ll,66- 116, 66-6, 66-23, 66-117, 66-i6, 66-19 and 66-26 produce an outputsignal on the output lines thereof which fire respectively thecorresponding pins of the light source After the first group of signalsrepresenting a character have been emitted by character source 76, apulse is produced on line 96 which shifts the ring counter of columnselector 62 and thereby energizes line 66-2 thereof. A second group ofsignals representing a new character is then emitted by source '76 onlines 76-11 through 76-26 and are fed to transformers 66-11 through66-26 via amplifiers '7 6-11 through 76-26.

simultaneously, the pulse on line 66-2 is fed via amplifier 66-2 totransformer 66-2 which supplies an input pulse to each of gates 66-11through 66-26. Thus, gates 66-11 through 66-26 are enabled to pass thecombinatorial signal pulses from transformers 66-l through 66-26 to thecorresponding pin electrodes 66 of light source 66.

As the characters supplied by source 76 are changed, pulses are fed vialine 66 to the column selector thereby sequentially energizing theremaining lines 66-31 through 66-7. in this manner a seven-digit numberis produced as each of the seven light sources 6'6 through 66 aresequentially operated.

The number of pin electrodes used in the system of FIG. 2 is 140 (20x7).It is seen that only 20 amplifiers were necessary from the charactersource and only seven amplifiers from the column selector. Thus, insteadof having to use 140 amplifiers to energize the electrodes of the lightsources, only 27 amplifiers are necessary. It is, of course, evidentthat if ten light sources were used only thirty amplifiers would benecessary. The amplifiers are, of course, replaced by inexpensive diodeswhich are used in each of the gates 66 through 72. Since only sevenamplifiers were used for selecting the columns and 20 amplifiers wereused from the character source, it is preferable to connect thetransformers of the column selector to the resistive inputs of thegates. In this manner, only seven highpower amplifiers are necessary todrive all of the l40-pin electrodes. The 20 amplifiers 78 which areassociated with the character source 74 are not required to behigh-power amplifiers because they merely inhibit the diodes of thegates from being forward biased.

Still further reductions of power amplifiers may be achieved by usingthe system shown in FIG. 3. The gates used in FIG. 3 are of thethree-input-type and are fired as a result of three selectingconditions. In this manner, instead of using 20 amplifiers to drive the20-pin electrodes of each of the light sources, only nine amplifiers arenecessary. Thus, in FIG. 3 rather than providing the 20 signals for anentire character simultaneously, only a row of signals is provided by arow of character source 92. Thus, the row OF character source 92 hasfour outputs 94-1 through 94-4 rather then the 20 outputs 76 ofcharacter source 74. Referring to FIG. 6, it is seen that the first rowof a character light source includes the in electrodes 48 in positions1, 2, 3 and 4. These pin electrodes are first fired combinatorially. Therow of character source 92 then produces on output, lines 94-1 through94-4 the combinatorial signal for the second row of pin electrodes inpositions 5, 6, 7 and 8. The source 92 then generates pulses on lines94-1 through 94-4 representative of the next row of a character. Theoutput lines 94-1 through 94-4 apply the signals from the row ofcharacter source 94 to amplifiers 96-1 through 96-4. Amplifiers 96 inturn produce an output pulse which is fed to transformers 98-1 through98-4. Seven light sources 100, 102...104 each having 20-pin electrodesare used in the system of FIG. 3. Twenty gates 106-1 through 106-20 areconnected to the pin electrodes 1 through 20 respectively of lightsource 100. It should be noted that each of the gates shown in FIG. 3 isrepresented as as semicircle having a dot therein and three inputs andan output. As seen in FIG. A and 5B the symbol is equivalent to a gatehaving resistor input 22, a diode input 24 and a second diode input 28which are connected together at junction 26.

Similarly, 20 gates 108-1 through 108-20 and twenty gates 110-1 through110-20 are connected to the respective pin electrodes of light sources102 and 104, respectively. There are also 20 gates associated with eachof the four light sources which are not shown. Row selector 112 ispreferably comprised of a conventional five-stage ring counter in whicha state at a time is energized. The row selector also includes anoscillator and gates which are used to provide output pulses on lines116-1 through 116-4 from the ring counter stage which is energized. Thesucceeding stages of the counter are energized by shift pulse form therow of characters 92 provided along line 114 after each row ofcharacters is changed.

Row selector 112 has five output lines 116-1 through 116-5 which areconnected to the outputs of the five stages of the ring counter. Fivepower amplifiers 117-1 through 117-5 amplify the pulses from the rowselector 112-1 through 112-5 respectively. The outputs of amplifiers117-1 through 117-5 are connected to transformers 118-1 through 118-5,respectively. Column selector 120 is similar to column selector 82 andhas seven output lines 122-1 through 122-7 which are taken from thevarious stages of the ring counter and gating circuitry which comprisethe selector. The ring counter of the selector is shifted along bypulses fed to the column selector via line 124 after all five of thelines 116 have been pulsed.

Thus, only afier a complete cycle of the row selector 112 is the columnselector changed.

The outputs of the columns selector 120 are fed to lines 122-1 through122-7 which are connected to power amplifiers 126-1 through 126-7,respectively. The amplified outputs are then transmitted to transformers128-1 through 128-7 which are connected to the output of amplifiers126-1 through 126-7 respectively.

Transformers 98-1 through 98-4 are connected to the four columns of thepin electrodes 48. Thus, referring to FIG. 6, it can be seen that theleftmost column of pin electrodes are in positions numbered 1, 5, 9, 13and 17. Therefore, transformer 98-1 is connected to the gates associatedwith these pin electrodes in each of the light sources through 104. Forexample, with respect to light source 100, transformer 98-1 is connectedto gates 106-1, 106-5, 106-9, 106-13 and 106-17. The transformer 98-1 isalso connected to the corresponding gates of the group of gates 108through Similarly, similarly, transformer 98-2 (not shown) is connectedto the gates associated with pin electrodes 2 6, 10, 14 and 18 in lightsources 100 through 104. The transformer 98-3 (not shown) is connectedto the gates associated with pin electrodes 3, 7, 11, 15 and 19 of thelight sources, and transformer 98-4 is connected to the gates associatedwith pin electrodes 4, 8, 12, 16 and 20 respectively.

Transformers 118-1 through 118-5 are each associated with a row of pinelectrodes 48 in each of the light sources 100 through 104. Referringagain to FIG. 6, it can be seen that pin electrodes in positionsnumbered 1, 2, 3 and 4 comprise the first row of a light source. Thus,transformer 118-1 is connected to gates 106-1 through 106-4, 108-1through 108- 4...1l0-1 through -4 which are associated with the pins 1through 4 of each of the light sources 100, 102...104. Transformer 118-2(not shown) is connected to the gates in groups 106, 108 and 110 whichare connected to pins 5,6, 7 and 8 of the respective light sources.

Similarly, transformers 118-3 through 118-5 are connected to the gatesin groups 106, 108 and 110 which are associated with the next three rowsof pins of the seven light sources 100, 102...104.

The transformers 128-1 through 128-7 which are activated by the columnselector are each connected to a different one of the groups of gates106, 108'through 110. That is, transformer 128-1 is connected to thethird input of each of the gates in the group of gates 106, transformer128-2 is connected to each of the gates 108 in the group of gates 108-1through 108-20... and transformer 128-7 is connected to each of thegates 110-1 through 110-20.

In addition to the various light sources, amplifiers, gates andtransformers which are not shown in FIG. 3 as well as in FIGS. 2 and 7,various conventional control circuits for maintaining timing andsynchronization of the elements of the system have not been shown. Inthis manner, the systems embodying the invention can more clearly beshown and succinctly described.

In operation, a first row of character signals is supplied at outputs94-1 through 94-4. These signals are amplified by amplifies 96 andtransmitted to the inputs of gates 106 through 110 by transformers 98-1through 98-4 respectively. Assuming that the first row is the rowincluding the pin electrodes in positions 1 through 4, the row selectoris at the start of a new cycle, therefore amplifier 117-1 is energizedby the pulse on output line 116-1 of row selector 112 and transmits apulse signal to transformer 118-1 which applies a pulse to each gateassociated with pins 1 through 4 of the light sources.

Assuming the column selector is in the start of a new column, the outputline 122-1 is pulsed thereby energizing amplifier 124-1 which transmitsa pulse to gates 106-1 through 106-20 via transformer 128-1. Thus,transformers 118-1 and 128-1 have both coincidentally applied a voltagepulse to diode gates 106-1 through 106-4. Gates 106-1 through 106-4 aretherefore enabled to pass the voltage output from transformers 98-1through 98-4 to pin electrodes 48 in positions 1 through 4 of lightsource 100. Thus, if any of these transformers were pulsed, thecorresponding pins in the row are firedl These are recorded onlight-sensitive paper (not shown) which is placed adjacent the lightsources lull through Mid.

During the change of the signals on the lines l d-l1 through f t-danoutput signal is applied to the row selector via line lllld therebyshifting the row selector lllil. which applies an output pulse on linelll6-2 which is passed to transformer lift-2. Transformer llllll-Il.pulse gates lllt5-5 through ltllti-ll of gates W6 and correspondinggates of the gates fifth and lllll. Transformer l2hl is pulsed againbecause column selector 12th has not been shifted. The gates enabled bytransformers lid-2 and llZh-ll are the gates lids-5 through llllltt-tlthereby passing the combinatorial pulse outputs from transformers @ll-llthrough 9ll-d which fire pin electrodes dtl in positions 5 through ll oflight source lltltl. After the second row is fired, the row of charactersource 92 supplies another combination of pulse signals. As the outputon lines Wl-ll through Ml-d change, a pulse is applied via line lllldwhich shifts the counter in column selector Jill and the next outputline l to of the row selector is pulsed. This results in the enabling ofgates filth-9 through lilo-l2 and the passing of the pulse signals fromtransformers fllhl through lidl to the selected pin electrodes inpositions it through 112 of light source Mill. The next row ofcharacters transformer llldd is pulsed as a result of the shift pulse online llld applied to row selector llllll.

The last row of characters which is passed to the light source llllll ispassed to pin electrodes l7 through as transformer ll ltd-5 is pulsed byrow selector llll2. During each ofthe five first steps, transformerlZli-l has received a pulse via amplifier lZll-ll from the columnselector mill which has remained in the same state.

After row selector T22 has completed a cycle by energizing output linesllll6-l through lilo-d consecutively, a shift pulse is transmitted online TM as the output line lilo-ll is pulsed again. The pulse on line1124 shifts the counter in column selector T22 so that llZZ-ll isdeenergized while line 122-2 is pulsed. Thus, transformer 128-2 isenergized thereby applying an enabling pulse only to gates Mill-lthrough 1108-20. Row selector lllIl has pulsed output line lilo-l and inturn energized transformer lid-l which is connected to gates lldil-lthrough llhd-d. Thus, the gates lllll-l through ltltl-d are enabled bytransformers lllltl-ll and lTzld-Zl to pass the outputs of transformershh-l through Ellil to fire the selected pin electrodes ll through d ofthe light source lllill. As the pulses emitted by the row of charactersource 92 change, the succeeding rows are transmitted to the secondthrough fifth row of pin electrodes of light source 1102.

After a row of a character has been steered to the fifth row of lightsource 1102;, the row selector llll2 transmits another shift pulse online 124 which changes the state of the counter of column selector 122to produce an output pulse on line llZZ-El. The line lZZ-Il continues tobe pulsed until each row of the next character has been steered to thelight source (not shown) which is associated with transformer lIltl-Zi.The succeeding light sources are each operated as transformers TEE-3through T26 7 are sequentially pulsed by the column selector l2ll. Afterthe last light source lltld has been operated, the column selectorcounter starts a new cycle and pulses the output line lZZ-ll thereof.The system is now ready to place a new worlc composed of sevencharacters into the seven light sources llllll to lltld.

It can be seen that by using both a row of characters and a rowselector, the system of FlG. 3 is capable of firing 140 pin electrodeswith only 16 power amplifiers.

in the system of FIG. 2., 27 amplifiers are needed to drive the 140 pinelectrodes. Thus a saving of eleven power amplitiers has been effectedby using the system of FIG. 3. In order to lower the number of poweramplifiers used it is nece sary only to provide an additional diode foreach electrode. That is, instead of having lldll gates each including asingle diode it is necessary to provide M0 gates each having two diodesfor inputs. l-lowevcr, diodes are relatively inexpensive compared topower amplifiers and a substantial savings is thus effected.

ill

it can be seen, therefore, that by increasing the number of conditionswhich it taltes to fire a pin electrode, the number of amplifiersnecessary can be reduced. Where only one condition is used to fire apin, lldtl amplifiers are necessary to fire pin electrodes. However,where two conditions were necessary to fire the electrodes, it was seenin MG. 2 that by adding l l-O inexpensive gates, the number of poweramplifiers could be reduced to 27. lily using three conditions to fire apin, it is seen in lFlG. ll that the number of power amplifiers could bereduced to 16 to fire each of the 140 pin electrodes.

in each case where the conditions were increased, there was afactorization of the number of the pin electrodes and the sum of thefactors equals the number of power amplifiers. That is, when increasingthe number of conditions to two, the number 140 was factored into thetwo numbers 7 and 20 which total 27. When increasing the conditions tothree, it is seen that the number of pin electrodes 20 in each lightsource was further factored into 5 and Thus, by using three condition,the 16 amplifiers were determined by adding 3 factors of the number 140(7, 4 and 5).

There is a point at which the increasing of the number of conditions totire a pin electrode reaches the point of diminishing returns withrespect to the reduction of amplifiers and any resultant saving in cost.in the example shown above, where seven light sources each having 20 pinelectrodes are used, increasing the number of conditions necessary tofire a pin to four can be done by factoring one of the factors '7, 5 or4- which were the factors when three conditions were used. The number 7which is the largest is a prime number. Thus, it does not have a pair offactors which evenly multiply to the number 7. Therefore, by using thenext higher number 8 which has two factors (2 and 4) which total 6 thenumber of amplifiers could be reduced by 1. Thus using four conditionssaves one amplifier. The saving of only one amplifier however, issomewhat off-. set by the increased complexity of the circuitry and theincrease in number of diodes that are necessary.

When factors equal to the numbers 5 or less remain, there can be noreduction in the number of amplifiers to fire the same number of pins.That is, the number 5 is a prime number and has no factors. Therefore,it is necessary to increase the number to 6. The factors for the number6 are 3 and 2 which total 5. Therefore, as many amplifiers are requiredfor four conditions as are required for three conditions. it can,therefore, be seen that for any combination of 5 or under, the rais ingof the number of conditions to fire the pins does not lower the numberof amplifiers.

Another advantage arising from the high-voltage gate embodying theinvention is the fact that the gates may also drive more than a singlehigh-voltage device at a time. That is, the high-voltage output atjunction 26 of the gate shown in FIG. l may be applied in parallel tomore than one pin. A gate utilizing this principle is shown in lFlG, ll.GATE llZili shown in FIG. 8A has four inputs. The first input includesresistor U2. The remaining three inputs include diodes 113d, T36 andF.3d respectively. Each of the inputs is connected to the others byoutput lead Mil. The output of the gate lldll is supplied to threeresistors 1142, Md and M6. lEach resistor may be connected to a separatepin electrode. lf a high-voltage input is applied to resistors U2 anddiodes lild, T36 and 1138 simultaneously, a highvoltage output isapplied to each of the re sistors lldll, lldd and Me which fire threepin electrodes concurrently. The resistors M2, Md, and M6 are requiredbetween the output lead l lil and each of the pin electrodes in order toprevent only one pin from firing at a time. That is, if three pins areconnected directly to output lead lldtl and each pin has a differentpotential caused by normal variations from wear, etc., when the pinhaving the lowest arcing potential fires, there is effectively 0 voltageat the conductor lldll. By providing resistors M2, ldd and lldd,however, the firing of the lowest potential does not lower the voltageat the output lead lldt) before the remaining two pins fire. it isunderstood, that plural outputs may be used with a gate embodying theinvention having any number of inputs.

The logic representation of the gate 130 is shown in FIG. 88. FIG. 7 isa logic block diagram of a system which incorporates these gates.

A photographic-printing system is diagrammatically illustrated in FIG.7. The printer is comprised of a hollow cylindrical drum 150 which hasalphabetic and numeric openings around the circumference thereof. Thedrum is elongated and has 72 rings or columns which are axially spacedand which each contain the entire alphabet and the numerals through 9.Each of the 72 rings of alpha numeric characters are aligned with eachother. Thus, all the characters lying along an axially extending line onthe periphery of the drum are of the same type. Thus, for example, allof the As are on the same line across the drum. Each of the charactersin the circumference of the drum are formed as openings in the wall ofthe drum. The drum rotates about its longitudinal axis. Light-sensitivepaper 152. is passed under the drum very close to the periphery thereofby means which are not shown. For each complete revolution of the drum150, the paper is moved one space. The paper is moved in the directionof arrow 154.

Running longitudinally within the drum 150 are 72 threearc light sources156. The light sources are axially aligned and are adjacent the axiallyextending line of characters adjacent the paper 152. One light source156 is associated with each column of alphanumeric characters about thedrum 150. Each light source requires only three arcs to completelyilluminate the back of a character to sufficiently record the characteron the light-sensitive paper 152.

A plurality of groups of three resistors are each connected to adifferent one of column light source 156. Each group of resistors 142,144 and 146 is connected to the output of a gate 130. Seventy-two gates130 are provided. Gate 130-1 is connected via the group of resistors142, 144 and 146 to the first column of alphanumeric characters on thedrum. Similarly, gate 130-2 is connected to a light source 156 viaanother group of resistors associated with and connected behind thesecond column of alphanumeric characters. Similarly, gates 130-3 through130-72 are connected to the light sources 156 which are associated withthe third through 72nd column of alphanumeric characters.

Thus, if any of the gates 130-1 through 130-72 is enabled by high inputsto each of the four inputs of the gate, the enabled gates fire the threepin electrodes within the associated light sources 156 thereby printingthe character on the light-sensitive paper 152. Gates 130-1 through130-72 are enabled only when four input pulses are coincidentallyapplied to their inputs.

Connected combinatorially to the inputs of the gates 130 aretransformers 158-1 through 158-12.

The gates 130-1 through 130-72 are grouped in fours for simplicity ofreference. Thus, reference made to the first group of four gates refersto gates 130-1 through 130-4, the second group of four gates refers togates 130-5 through 130-8 and similarly the l8th group of gates refersto gates 130-69 through 130-72. The transformers are connected in thefollowing manner to the gates:

l. Transformer 158-1 is connected to each of the first 36 gates 130-1through 130-36.

2. Transformer 158-2 is connected to each of the first 24 gates 130-1through 130-24.

3. Transformer 158-3 is connected to the first gate of each of the l8thgroups of gates. That is, gates 130-1, 130-5, 130-9,130-13,l30-17,130-21...130-69.

4 Transformer 158-4 is connected to each of the four gates in the first,fourth, seventh, 10th 13th and 16th group of four gates.

5. Transformer 158-5 is connected to the middle 24 gates 130-25 through130-48.

6. Transformer 158-6 is connected to each of the four gates in thesecond, fifth eighth, llth l4th'and 17th group of four gates.

7. Transformer 158-7 is connected to the third gate of each group offourgates (130-3, 130-7, 130-11...).

8. Transformer 158-8 is connected to the last 24 gates 49 through130-72.

9. Transformer 158-9 is connected to each of the four gates in thethird, ninth, 12th 15th and 18th group of four gates.

10 Transformer 158-10 is connected to the second gate of each group offour gates (130-2, 130-6, 130-10...).

11. Transformer 1513-11 is connected to the last 36 gates 130-37 through130-72.

12. Transformer 1521-12 is connected to the fourth gate of each group offour gates (130-4, 130-8, 130-12...

In this manner, 12 transformers which are connected to the outputs of 12power amplifiers are sufficient to drive each gate individually bypulsing various combinations of four transformers 158 simultaneously.

As previously mentioned, the twelve transformers 158 are connected to 12power amplifiers which are not shown. The amplifiers are in turnconnected to computer circuitry which determines when each of thetransformers is to be pulsed. That is, the circuitry which determinewhich transformers are pulsed include apparatus to sense the rotationaldisposition of drum 150. This information is converted into signalswhich correspond to the position of the drum. These signals are comparedwith those which are to be printed at the various positions along aline. Thus, if an A is to be printed at the first, third and 69thposition of a line, when the position of the drum is such that the rowof A's are adjacent the light-sensitive paper, the transformers 158-1,158-2, 158-3 and 1584 are first pulsed simultaneously thereby enablinggate 130-1 to fire the pin electrodes of the light source 156 behind thefirst column. The firing of the three arcs of light source 156 therebyprints a letter A in the first column. After gate 130-1 has beenenabled, transformers 158-1, 158-2, 158-4 and 158-7 are next pulsedsimultaneously thereby enabling gate 130-3 which in turn fires the threepin electrodes within the third light source 156 and therebyphotographically printing an A in the third column.

After the termination of the enabling signal on gate 130-3, transformers158-3, 158-8, 158-9 and 158-11 are simultaneously pulsed therebyenabling gate 130-69 which in turn fires the pin electrodes of the lightsource 156 associated with the column 69 of alphanumeric characters.Thus, an A has been printed in the first, third and 69th positions ofthe line. The drum is then rotated to the position where B is locatedbetween each of light sources 156 and the paper 152. If any B's are tobe printed, then the position in which a B should be printed in the lineis detected by the computer controlling the energization of transformers158-1 through 158-12 so that the gate 130 associated with the properposition on the line is enabled. Similarly, the drum continues to rotateand as letters pass through the light sources nd the paper that are tobe printed in the remaining positions of the line, the transformers arecombinatorially energized to enable the proper gate 130 to fire the pinelectrodes in the proper light source.

After one complete revolution of the drum, all of the letters ornumerals to be printed in a line will have been printed.

After each complete revolution of the drum 150, the photosensitive paper152 is moved one line so that the next line can be printed.

It can be seen that by use of the gate 130 at each of the positions 1through 72 corresponding to the 72 light sources 156, it is possible toreduce the number of power amplifiers necessary to fire the 216 arcsassociated with the 72 column light sources 156 from 216 to 12. That is,by using each gate to fire three arcs at a time rather than one, thenumber of amplifiers necessary is reduced from 216 to 72 (2163).Further, in accordance with the discussion hereinabove, by increasingthe number of conditions necessary to enable each gate to operate thelight source, the number 72 is factored into smaller components. Thus,the factors 2X3X3X4 were derived. Adding the factors together results inthe number l2. Thus, only 12 amplifiers are necessary to combinatoriallyselect each of the 72 gates 130 one at a time. Thus by using fourconditions to enable the gates 130, the number of amplifiers is reducedfrom 72 to 12.

Thus, the gating systems embodying the invention require less poweramplifiers to drive a predetermined number of high-voltage devices. Thegates used are each responsive to a plurality of conditions foroperating the devices. Additionally, where a plurality of devices are tobe operated in the same manner, a single gate may be used to tire themconcurrently. The resulting need for less amplifiers enables the outputdevices to be packaged with the gating circuitry and thereby loweringpackaging costs as well as reducing the size of the devices.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed as the inventions is:

l. in combination a gate having a plurality of input means and an outputmeans commonly connected to each of said input means, a plurality ofhigh-voltage pulse sources, each of said pulse sources being connectedto a different one of said input means via a transformer, one of saidplurality of input means including a resistor, the remainder of saidplurality of input means each including a diode, said output means ofsaid gate being connected to a pin electrode for use in printing acharacter, said gate adapted to energize said pin electrode only uponsimultaneous application of pulses to all of said input means.

2. The combination of claim ll wherein said pin electrode is provided incombination with a bar electrode to form a light source adapted toprovide light for use in printing a character on adjacentlight-sensitive paper, said gate adapted to tire said pin uponenergization of said electrode.

3. A plurality of gates of r use in a recorder having a plurality ofultraminiature are lamps each including electrodes requiring high-inputvoltage for operation thereof, said electrodes being provided in apattern, each of said gates comprising a plurality of input means eachconnected to a different high-voltage pulse source and an output meanscommonly connected to said input means and directly connected to adifferent one of said electrodes, one of said plurality of input meansincluding a resistor, the remainder of said plurality of input meansincluding a diode, said plurality of input means being connected to saidoutput means so that each gate energizes one of said electrodes uponcoincidence of a pulse generated at each of said voltage sourcesconnected to said gate.

Patent No.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated November 2,1971 Andrew E. Trolio and Edward G. Busch It is certified that errorsappear in the aboveidentified patent and that said Letters Patent arehereby corrected as shown below:

Column 5, line 59 Column 5, line 65 after the numbers "76-20" insert theword as-.

"in" should be Column 7, line 31 -pin-.

"94" should be Column 7, line 39 "state" should be Column 7, line 58stage--.

"form" should be Column 7, line 62 from--.

Column 8, line 18 after the word "through" insert the number ll0,.

line 18 omit the word second occurence.

Column 8, "similarly",

Column 8, lines 58 and 59 "amplifies" should be -amplifiers--.

Column 9, line 24 after the word "characters" insert the following:

from source 92 is then passed to pin electrodes 13 to 16 as.

Signed (SEAL) Attest:

EDWARD PLFLMTCHER,JR. Attesting Officer line 33 "122" Column 9, shouldbe Column 9, line 61 "work" should be word.

Column 12, line 51 "nd" should be -and.

Claim 3, line 9 "of r" should be -for-.

Claim 3, line 10 "are" should be --arc--.

and sealed this 25th day of April 1972.

ROBERT GOTTSCHALK Commissioner of Patents

1. In combination a gate having a plurality of input means and an outputmeans commonly connected to each of said input means, a plurality ofhigh-voltage pulse sources, each of said pulse sources being connectedto a different one of said input means via a transformer, one of saidplurality of input means including a resistor, the remainder of saidplurality of input means each including a diode, said output means ofsaid gate being connected to a pin electrode for use in printing acharacter, said gate adapted to energize said pin electrode only uponsimultaneous application of pulses to all of said input means.
 2. Thecombination of claim 1 wherein said pin electrode is provided incombination with a bar electrode to form a light source adapted toprovide light for use in printing a character on adjacentlight-sensitive paper, said gate adapted to fire said pin uponenergization of said electrode.
 3. A plurality of gates of r use in arecorder having a plurality of ultraminiature are lamps each includingelectrodes requiring high-input voltage for operation thereof, saidelectrodes being provided in a pattern, each of said gates comprising aplurality of input means each connected to a different high-voltagepulse source and an output means commonly connected to said input meansand directly connected to a different one of said electrodes, one ofsaid plurality of input means including a resistor, the remainder ofsaid plurality of input means including a diode, said plurality of inputmeans being connected to said output means so that each gate energizesone of said electrodes upon coincidence of a pulse generated at each ofsaid voltage sources connected to said gate.